1. Field of the Invention
The present invention relates to an ink jet ink, a method for producing ink jet ink, an ink jet recording method and an ink cartridge.
2. Related Background Art
An ink jet recording method is a recording method of applying a small ink droplet to any one of recording media such as plain paper, glossy media and the like to form an image, has become rapidly widespread owing to reduction in its costs and improvement in its recording rate. In addition to improved quality of the recorded image, and concurrently with the rapid spread of digital cameras, users of the ink jet printers now demand to output recorded matter which is e comparable to a silver halide photograph.
A necessary requirement for a recorded matter which is obtained from an ink jet recording method to be comparable with a silver halide photograph, it is cited that both high color developability and durability of the obtained recorded matter are realized simultaneously. Compared with silver halide photographs, a recorded matter obtained from a conventional ink jet recording method has especially low durability, and when exposed for a long period of time to factors such as light, humidity, heat and environmental gases present in the air, the coloring material on the recorded matter would deteriorate. There has been, therefore, a problem that such recorded matters were susceptible to varying in color tone and fading of the image. Of the above-mentioned environmental gas, deterioration of the recorded matter from ozone is a particular problem.
Among the respective inks of yellow, magenta and cyan that are used in an ink jet recording method, cyan ink is the most susceptible to deterioration in durability (particularly ozone resistance). Thus, improving the ozone resistance of the cyan ink to match that of the yellow ink or magenta ink is an important matter.
The basic skeleton of coloring materials for ink jet ink having a cyan hue are roughly classified into a phthalocyanine skeleton and a triphenylmethane skeleton. Representative coloring materials of the former include C.I. Direct Blue 86 and 87, C.I. Direct Blue 199 and the like. Representative coloring materials of the latter include C.I. Acid Blue 9 and the like.
On the other hand, to improve environmental gas resistance, as represented by ozone resistance, inks which comprise a dye having a specific structure which exhibits extremely good environmental gas resistance have been proposed (e.g. see Japanese Patent No. 2942319).